Yes and no, you would need to change the body class token body.register is particular to the registration page so you would need to do something like:
`
body.page-id-1215 #content,
body.register div#content {
margin-right:0;
padding:0;
width:100%;
}

`
page-id-1215 is the only unique identifier of that page.

However this approach isn’t really the best one, it would be better to be using a onecolumn-page.php template that has the sidebar removed as is provided in the bp-default theme then you would select that page template for you terms&conditions page and when 1.3 hits you would do the same for the registration page.

thanks so much, the above approach worked, Am using a child theme created by me, but i copied all the files from bp-default theme and customised it. where can i get the onecolumn-page.php template? am not developer but its only help from people like that push me this far

`
Not sure if this is practical as it is from 1.3 but the principle is sound. You would need to ensure your custom markup – if any – was replicated in this page and change the top template notice to 1..28 this would then give you a selectable template for when you create any pages that don’t require sidebars. When 1.3 lands live you will also be able to use templates for regular BP pages such as registration as 1.3 uses pages for the main components.